One of the safeguards against someone being convicted on evidence
obtained as a result of
an illegal search is the Fourth Amendment-based Exclusionary Rule. The theory is that if police want a conviction, they will be careful to obtain evidence according to proper procedure, or the evidence will be excluded from any trial.

But what if police are more interested with making an arrest and seizing contraband than actually getting a conviction?

You’re bum out of luck.

If there is no concern for actually getting a conviction, there is little to keep the police from violating citizens’ Fourth Amendment rights. Police will sometimes go ahead and make an arrest for possession of drugs, notes the Stanford Law Review, “even if (an officer) is aware that it will not stand up under judicial scrutiny.” Why, you might ask. “At minimum he will have confiscated a supply of an illegal drug. The defendant will be jailed and have to post bail, and in many cases will have to hire a lawyer; these alone serve a punishment.”

Clearly, the Exclusionary Rule keeps unlawfully obtained evidence out of courts — but that’s all. Joe Citizen may still have his rights trampled even if he is not the subject of prosecution. In fact, a citizen who is not aware of his rights and the illegality of a policeman’s search might very well plea bargain for a lesser offense rather than risk a felony conviction, not realizing that there was never a real case against him in the first place.